Borehole washing device



April 1l, 1950 A. D. GARRISON BOREHOLE WASHING DEVICE Filed Jan. 10,1948 WwVVVV/V/r//V/Vy//M//f///////MVVVV/VVMVVVVV Iii) y l INVEN TOR. AL5 GAR /5 N Patented Apr. 11, 1950 UNITEDfS-TATES PATENT oFF-ICE y i' BOREHOLE WASHING DEVICE Allen D. Garrison, Houston, Tex.', assgnor to.Texaco Development. Corporation, New York, N. Y., a. corporation. ofDelaware f f Application January 10, 1948, Serial No. 1,618

This invention relates to washing devices for bore holes or wells, andmore particularly to a device through the use of which a stream ofwashing fluid will be caused to pass through restricted areas or zonesin intimate contact with the material which it is desired `to removefrom the walls of the hole, such as drilling mud cake. The principalobject of the invention is vto pro- ,vide a device of this kind which,when attached to the lower end of a string of tubing or drill pipe canbe expanded to restrict -the annular space between the .tubing and thewalls of the hole without the-necessity of valves orA other elementsrequiring control from the surface..

'Y As is well known, when drilling a bore hole a uid such as mud'iscommonly; used for carrying the. cuttings upwardly to the surface.yAnother function of the fluid is yto plaster and to form a cake of themud on the inner surfaces of the hole to prevent sloughing of theformation walls into the hole, to prevent water from filtering into thehole, etc. After'the casing has been set in the hole,vit is desirabletoremove the mud cake from the walls of the oil bearing formation and thishas frequently proven quite difficult.

Ithas been found that where gravel has been packed between the ow tubingand the walls of Athe producing formation, wateror other liquid forceddownwardly to the 'bottom of the tubing string and then upwardly.through the gravel `pack tends towash the mud from the formation ywallseffectively, this being due to the fact that lthe restricted passageswithin the gravel and between the gravel particles and the walls of theiformation increase the velocityv of the liquid. Obviously when thewater issuing from the lower end of the tubing string is permitted topass upwardly through an annular space as large as that between thetubing and the walls of the hole the Velocity is'greatly reduced andmuch of the water does not come in contact with the mud cake withsucient velocity to remove the mud. f

In accordance with this invention an expansible balloon-like member isaixed to the lower endl of a tubing or drill pipe string. with means for:maintaining the member normally in/it's'longit'udinally extended,horizontallycontracted position, When liquid is forced downwardlythrough the string a portion will pass outwardly at the bottom of thestring and will then pass upwardly through the space between the wallsof the hole and the retracted member. Another portion, however, willpass from the tubing string into 10mm. (ci. 16a-18) the member to causeit to expand laterally 55 Fig. 3.

2 v toward the walls of the hole andy this will concentrate the flow ofthe washing liquid pastthe mud cake, this restricted area being adjacentthe mud cake on the formation walls. The outer surface of the expansiblemember is preferably provided with spines or other pointed elements,which tend to penetrate the mud cake so as to break it up. lThe outersurface is also provided with a plurality of vanes or bames which engagethe formation walls so as to hold the body of the expansible member inspaced relation to the lwalls without materially interfering'with theAilow of liquid. Inthis manner the washing liquid passing outwardlythrough the bottom ofthe tubing string is forced upwardly through thevanes and spines so as to effectively wash the mud cake from the walls.The device can be lowered or raised in steps while beingretracted andexpanded so that all of the surface ofthe formation walls will becleaned of the mud cake, or it can be lowered or raised continuouslywhile the washing fluid is flowing, for the same purpose. -For a betterunderstanding of the invention reference may be had to the accompanyingdrawing, in which Fig, l is a Vertical sectional elevation showing thewashing device in retracted position being lowered through the casing;1;

Fig. 2 is a cross-section on the line 2 -of Fig. 3 is a View similar toFig. 1 but showing the washing element in its expanded orcleaningposition against the formation walls, and

Fig. 4 is a cross-section onthe line d-tof Referring to the drawing, asection of a bore hole I0 is shown as .provided with a casing I2.cemented in place, as indicated diagrammatically at I4.- With referenceto Fig. 3, the lower portion ofthe bore hole is illustrated aspenetratingfa producing formation I6 and on the walls of the producingformation below the casing l2 is shown ca mud cake orlayer I8, the mudhaving been deposited during the drilling operation.

'A pipe string 20 which may be tubing, liner or drill pipe has attachedto its lower endampipe section 22 having a few wall perforations 24 anda somewhat restricted opening 2l at its bottom. An expansibleballoon-like member 26 of rubber or other flexible material andpreferably somewhat elongated in shape is firmly attached at its upperend to the upper exterior of the pipe section 22 as by cementing to orsqueezing between rings 28, threaded or welded onto the pipe. The lowerend of the member 26 is shown as provided lwith an opening, the edge ofwhich is disposed in a channeled ring member 30 adapted to slide looselyupon the exterior of the pipe 22. Within the member 26 and surroundingthe pipe section 22 is a coiled compression spring 32 adapted to forcethe lower end of the member 26 downwardly, away from the upper end sothat the member will be longitudinally extended and laterally retractedwhen the device is being run into the bore hole, as shown in Fig. 1.

The outer side surfaces of the expansible mem ber 26 are provided with ayplurality' of .spines or spikes 34 which may be of rubber, metal, orother suitable material. Disposed longitudinally along and in spacedrelation 4about the exterior surface of the member 26 are a plurality ofvanes or baiiles 36 which also may `be of rubber lor metal, the purposeof which is to hold the outer surface of the expansible member slightlyspaced from the walls of the hole when the member is in Iits vexpandedposition to prevent the member :26 from fpackingzoii the annular ispace.If the vanes 36 are yof rubber the-y may comprise continuous strips`extending up 4and down the sides ofthe fexpansible member. Ii, however,the vane's are of metal or other non-flexible material, they may beformed in a :plurality `of Ashorter sections Islightly separated fasindicated `by spaces 138.

As 'shown in Figures 1 and 2 when there is no 'iiu'id under pressurewithin the tubing '223, the

member '26 will remain .in its vlaterally contracted "positionvdue tothe pressure exerted by the spring "32. In this position, 'the devicecan be easily run finto a cased hole as shown in Fig. l to Aa position-below the bottom Vof the casing as shown in Fig.13. Assuming that wateris `used 'as vthe washiing fluid, this water being forced downwardlythrough the tubing string 20 will pass outwardly th-rough the 'bottomopening 27 and then upwardly as indicated bythe arrows 49 in Fig. V3.

At-the same time a portion ci the water will pass fbe compressedsomewhat due 'to 'the vertical shortening of the expansible member. 'Thestuds, or spines, 34 will penetrate 'the mud cake I8 while the vanes 3Swill come to rest against the walls of the formation "SG, thusmaintaining a restricted annular space between the outer surface of themember 2i; and the formation walls.

"The spines ad andthe varies '36 willftend to break up the mud cake i3and will also provide some 1 turbulence of flow of the wash waterinpassing "upwardly around the sides of the expansible member. 'In thismanner the mud cake will be fqu'ickly and completely removedfrom Ytheforma- -f-'tion walls, the removed mud flowing upwardly f1 to thesurface with `the returning wash water. 'If vdesired the vanes 35 may bedisposed in a `spiral formation up and down 'the outer surface of themember "2li,

As stated hereinbefore, after a section of the -iformation wall has-beencleaned the tubing string 20 may be lowered or raised a distance equal'to `.the expanded length of the member 25. In doing CII Lil)

"said valles and spines will enga-ge the walls 'the hole.

ascetic thisthe ow ofl water downwardly through the tubing 20 may bestopped, thus permitting the member 26 to return to its retractedcondition afterv which it will again be expanded when the device hasbeen raised or lowered to the next cleaning position. If desired, themember 26 may remain in its expanded position while the tubing 2li 4ismoved continuously up or down along the formation walls, the spines 34serving toabrade and scrape the mud cake from the walls at the same timethe mud is being washed :away by the lupwardly flowing water.

Although the device has been described With particular reference to thecleaning of mud cake other uses will 'be'apparent For example, a similarexpansible member may be disposed about the casing latsome point abovethe conventional cementing shoe. When expanded the cement would `beforced to the outside of the hole and by thus increasing the Velocity ofthe rising cement vslurry the wall of the hole would be cleaned of vmudcake lto 'insure a uniform bond of the cement `against the formation. Inthis instance the Ydevice would :in all probability be left in the `holefafter'the cementing operation.

Obviously many rnomii'iications and variations of the invention,ashereinbefore set forth, may be vmade without departing from theAspirit tand yscope thereof, -and therefore lcnly :suchllimitationslshould be imposed l.as 'are indicated in the apfpended claim.

I 'claimt A bore hole vwashing device comprising a string of tubingadapted to lbe lowered into 'said hole, the bottom end of said tubingbeing provided Nwith 'a ydownwardly directed opening smaller in diameter'than Vthe interior of `said tubing, an ex. `pansible balloon-likemember encircling said tub jing near its lower end, one end of saidmember being rigidly attached to said tubing and the other end havingloose, sliding engagement with the outer surface of 'the tubing, a`plurality of nexible substantially vertical 'vanes projectingyoutwardly 4from the /ou'ter surface fof said member, 'a plurality vcispines lalso projecting outward- '1y ifi-om the v'outer surface iofvsaid member ybe- #said last-mentioned opening into said lballoonlikemember to expand it vhorizontally so that ldi ALLEN D. fCSQXRRISOIViREFERENCES CITED The following references are of record in the 4nie oi"this ipatent':

UNITED `STATES PATENTS

